Saturday, March 08, 2008

Wolves, Pronghorn, and Coyotes

I have often written about the trophic cascade effects of a top predator. Trophic cascade refers to the cascading effects on an ecosystem from the presence of a top predator. It ranges far beyond the direct predator-prey relationship. For example, wolves move elk from the rivers, encouraging more willow and cottonwood growth, benefiting beavers and moose. Beavers in turn benefit trout by creating more habitat. The cascade continues.

A new research study just published by the Wildlife Conservation Society provides more data regarding the interdependency of wolves, coyotes, and pronghorn - Are Wolves The Pronghorn's Best Friend? The study measured the pronghorn fawn survival rates in wolf abundant areas and in wolf free areas. The fawn survival rate in wolf free areas was only 10 percent, while it was 34 percent in wolf abundant areas. The key difference is that wolves keep the coyote population in check. Coyotes, not wolves, prey directly on pronghorn fawns.

It is interesting that the State of Idaho is currently paying money to kill coyotes and will soon launch a money losing proposition to kill wolves. This is all because we feel some inherent need to "manage" wildlife. If history repeats itself, which all indications are that it will, our "management" will result to be more like "meddling" resulting in even more problems.